Lucky Cases mod adds a bunch of cases, which combine all the items, that are registered in your Minecraft. So you don’t have to worry about other mods, items from other mods are automaticially added to the cases and sorted correctly. Like in CS:GO, your items can have different conditions, Untouched, Minimal Wear, Used, Well Worn, Scarred.
These conditions do affect the durability of the items you will get. Also you have a on the rarity depending chance of getting an fully enchanted item. You can’t craft these cases, like in CSGO, you can get them by playing. Actually you will get a bunch of them every 10 minutes. But you still need a key to open them.